Yes, you can "Undo" a Jailbreak, by going into iTunes and Restoring your iPod Touch, or iPhone.
how do you undo your tagged photo which I erase
Fn insert
iTS IRREVERSABLE I DID THE SAME THING
Undo the bolt
Double tap and undo typing or delete option should appear on screen.
Yes, you can undo the jailbreak. You have to restore your
sync it using itunes that should do the trick
Full Screen Mode: the F11 key toggles Full Screen Mode on and off.
switch from lock to unlock
Undo the rivet under the lock, pop the black clip out and the lock slides out.
There is no way to undo iOS 7 after restoring your iPod because iOS 7 is not released yet. However, to downgrade the iOS of your iPod simply download the firmware of the iOS you want from the Internet. While in iTunes, hold shift as you click "Restore my iPod to factory settings" and choose the file you just downloaded and your iPod should be on a lower iOS.